Warning: This story contains major spoilers from Thursday’s episode of How to Get Away with Murder. Read at your own risk!

How to Get Away with Murder’s killer is not a bad guy—according to the actor who portrays him.

When Harry Potter alum Alfred Enoch signed on to play the unassuming waitlist student fondly referred to as the “puppy,” he was unaware that his character would ultimately be the one who killed Sam (Tom Verica). In fact, he didn’t even learn that Wes would strike the deathblow after Annalise’s (Viola Davis) husband started choking Rebecca (Katie Findlay) until the cast gathered for the table read of the winter finale.

Still, Enoch is quick to defend his character when EW hit the set of the ABC drama, explaining that this side of Wes could’ve been lying dormant all along—a side effect of his mother killing herself, perhaps?—but the genuine catalyst to take such a drastic measure was his want to protect Rebecca. What does that mean for his future? Enoch explains:

EW: You joked earlier in the season that Wes was a Gryffindor, but now he’s totally become a Slytherin after killing Sam!Alfred Enoch: Gryffindor could do that! The basilisk has feelings, but Harry still kills that.

Did you know from the beginning that Wes was the killer?
No, I didn’t know. I wish I had, but I didn’t know. I found out when we got the script. I conjectured. There was one scene in episode 7 when I was like, “I must’ve done it or this scene doesn’t work.” If it was Rebecca who did it, that didn’t quite make sense with the scene. The way that scene made most sense was if I did it, but even then, that wasn’t a guarantee that I did it. There were little hints. For a while, I could understand Wes doing it. I could see him doing it if it was to defend Rebecca and that’s how it turned out. It shifts the playing field in a way that good mysteries do. They get you obsessing about the one question, but then they answer that question and go, “That’s not really the question, the question is how?” The twist is something other than just being someone you’re not expecting it to be. I thought it was really cool.

Do you think the point of having him be the ultimate killer was to corrupt him after coming in as this bright-eyed student?
I’m not sure that’s quite how I see it. People don’t come in molded by their future actions necessarily. You have a character who does something bad, but that doesn’t mean they are a bad person. Good people can do bad things. It’s an inevitable turning point, a real shift in his life in what happens next and who he’s becoming and who he goes on to become later. Really, it has to be because of how important Rebecca is to him, but that might’ve happened a year ago. It’s not like Wes coming to law school [was the cause], there are a lot of factors that lead up to it. That fierce protectiveness is an essential quality. [Showrunner Pete Nowalk] and all the rest of the writers managed to find a way to exploit that and to use that to do it in a surprising and dramatically interesting way.

Annalise was in the house and saw Sam’s dead body. How does that change their relationship moving forward?
It binds them even closer. They’re, in a way, constantly getting bound closer and closer together, even up to episode 9, but that’s something else that makes them more inseparable. I don’t mean inseparable like they spend a lot of time together, but they have to stick together. There are things that tie that knot between them even tighter. Not to speak for the other students, but Wes has cause to be skeptical of Annalise and that increases with each passing episode. He finds out something else and he’s just like, “This woman! What the hell?!” and trusts her less and less. This turns that upside down.

Wes murders Sam for Rebecca. How does that change their relationship and what was behind that? Was is just about his love for her?
Yeah, that and he needs her. I don’t think he can bear to lose her. That’s unacceptable. That is the ultimate loss for him. He has to protect her in that moment. I see that. To me, it doesn’t demonize him, that act. I’m not saying it’s a good thing that he does it or even justifying it, but that doesn’t denounce him utterly for me at all. He acts to protect her. He acts out of love. He acts out of need as well.

The cops will be questioning them. How is Wes dealing with that? Can he trust the rest of the Keating Five?
It’s a fascinating dynamic because everyone is out to protect themselves if they can. People in that kind of stress, the characters are prosecuting their own intentions and objectives even more drastically than before because the stakes are so high. Everything is so vital. Wes has an interest to keep them all together. There’s the potential for a lot of secessionism, for want of a better word. His fear is that some of them think, “Shit, I didn’t do it. I didn’t hit someone on the head. I didn’t kill anyone. I didn’t push anyone over the banister. I’m going to wash my hands of this, say they’re responsible and get away with it.” He can’t afford for that to happen. That push-pull, thematically, is very interesting and hopefully continues to be explored.

How to Get Away with Murder returns Thursday, Jan. 29 at 10 p.m. ET on ABC.

Want more scoop on Murder? Read our interview with the victim here and our interview with showrunner Pete Nowalk here.